Touch display devices may detect the coordinates of a finger in the plane of the display screen in the touch display device by using touch electrodes, and correspondingly display according to the coordinates.
In existing touch display devices, the touch function is mainly implemented by two touch electrode layers, each touch electrode layer including a plurality of touch electrodes disposed in parallel with each other, and the two touch electrode layers being orthogonal to each other. Touch excitation signals are applied to touch electrodes in one touch electrode layer. When a person's finger touches the screen of the touch display device, a coupling capacitor is formed between the finger and some touch electrodes on the screen, and a leakage current flows out from the coupling capacitor. A touch detection circuit determines, by detecting the leakage current, two orthogonal touch electrodes in the two touch electrode layers that form a coupling capacitor with the finger, so as to determine the touch position.
Referring to FIG. 1, a schematic structural diagram of a conventional touch display device is shown.
A touch transmitting electrode layer 110 includes a plurality of strip-shaped touch transmitting electrodes 111. A touch sensing electrode layer 120 includes a plurality of bar-shaped touch sensing electrodes 121. The extension direction of the touch transmitting electrode 111 is orthogonal to the extension direction of the touch sensing electrode 121, and each touch transmitting electrode 111 overlaps partially each touch sensing electrode 121. That is, each of the touch transmitting electrodes 111 forms a capacitor with each of the touch sensing electrodes 121 at the overlap. The touch position is detected according to the variation in capacitance.
In addition, the touch display device further includes an integrated circuit (IC) 130. Each touch transmitting electrode 111 is electrically connected to the IC 130 through a touch scan signal line 112, and receives a touch scan signal that is output by the IC 130. Each touch sensing electrode 121 is electrically connected to the IC 130 through a touch sensing signal line 122, and sends a collected touch sensing signal to the IC 130.
However, when an architecture as shown in FIG. 1 is used, if the screen size of the touch display device is large, a large number of touch transmitting electrodes and touch sensing electrodes need to be provided in order to ensure certain touch detection accuracy. As a result, the number of touch scan signal lines connected between the touch transmitting electrodes and the integrated circuit increases accordingly, and the number of touch sensing signal lines connected between the touch sensing electrodes and the integrated circuit also increases accordingly. Consequently, the touch scan signal lines and/or the touch sensing signal lines require more space, leading to an increase in the bezel width of the touch display device, which is contrary to the current development trend toward narrow-bezel display devices.